Alpha-fetoproteins are hormones secreted by a human fetus. Their levels elevate during pregnancy, but they are no longer detectable several days after childbirth. In an adult, an alpha-fetroprotein is a tumorous marker, whose dosage permits the detection of certain types of cancer, notably testicular and ovarian cancers. The levels of alpha proteins rise in the case of certain liver diseases (i.e. hepatitis) and stomach cancer.